Smoke-preventing device for boilers and furnaces



Jgm. 22,-1929. 1,699,832

T. D. CASSERLY SMOKE PREVENTING DEVICE FOR BOILERS AND FURNACES Filed Dec. 14, 1925 i9 2720mm D. Casfier/" Patented Jan. 22, 1929.

UNITED STATES 'PATNT "FFimj THOMAS Davin CASSEBLY, or GHIGAGO, ILLINOIS.

SMOKE-PREVENTING DEVICE FOBBOIIZEBS AND FURNACES.

Application filed December nace and more especially to the combustion space in the rear of the furnacea-nd in back of the bridge wall so as to combine and mix with the gases and products of combustion and insure complete combustionand burning thereof, whereby the fuel will be thoroughly consumed and the emission'thereof from the chimney in the form of black smoke eliminated, thus assuring the highest efiiciency for the fuel consumed, in addition to avoiding the smoke nuisance, especially with soft coal. 7

Another object of the invention is to provide a smokeless boiler of the transverse vertical sectional type having front, back, and a plurality of intermediate sections with a top arched portion, depending side legs and inwardly extending webs so formed that the webs of two adjacent intermediate sections are spaced to receive hollow wing arches or auxiliary atmospheric air supply boxes above a fire wall dividing the boiler into a front fire box and rear combustion chamber or main front combustion chamber and rear auxiliary combustion chamber so that the products of combustion will be completely consumed, and whereby all of the intermediate sect-ions may be made of the same pattern and yet variations in thesize of the fire box and relative sizesof the fire box and combustion chamber may be obtained accordingto the capacity required.

It is also an object of the invention to supply air to the combustion space by means of a novel construction of auxiliary air admission tube or conduit which causes a whirling action of the auxiliary air which is ad mitted into the combustion space over the bridge wall on opposite sides of the furnace with such direction as to insure complete mixing thereof with the burning gases from. the the box chamber of the furnace. By reason of being subsequently caused to pass through a circuitous or tortuous back and forth travel complete absorption of the heat thereof is insured, while novel means is also provided for automatically regulating the supply of auxiliary air to join with the gases and products of combustion for the purpose it, 1925. seri l No. 75,202.

of securing complete consui'nption of the fuel and elimination of smoke, in addition to permitting the auxiliary air to enter in proper proportion to the fuel consumption or the amount of heat required under varying weather conditions" and temperatures.

Other and further objects will be apparent as the description proceeds. In the accompanying drawings, Fig. l is a sectional side elevation of a sectional or square type of furnace or boiler equipped with my improvements. Fig. 2 is a vertical, transverse, sectional view taken on the line 22 of Fig. 1.

Fig. 3 is a detailed sectional, perspective view of one of the hollow air inlet boxes constituting a part of the device. i Fig. 4 is a detailed sectional view of th air inlet tubeor conduit, and Fig. 5 is a detailed horizontal, sectional view of the air inlet box of a modified form.

Referring to the drawings in detail, a boiler 6 is shown, the same being of the sectional or square type for the purpose of illustrating the application of the invention. This boiler comprises a base section? and a sectional or other base extension 7 horizontally arranged, and a series of vertical sections including a front section 8, intermediate hollow-arched sections 9, and a rear section 10 which is closed at the back, double- T walled and hollow'like the front section 8, as indicated at 11. All of the sections are hollow to provide water and teanrcontaining chambers 12. The front section 8 is provided with a fuel supply orfire door 18 and an ashpit 'door 14 is provided therebelow, communicating with the ashpit 15 beneath the grates 16, through which the primary supply of air and oxygen to support combustion passes, over which is the firebox 17.

In most instances, the grates terminate short of the rear section of the furnace and a bridge wall or baffle 18, preferably of firebrick is provided on the base extension 7 in back of the front base section 7 and extending transversely across the same between the depending legs of two of the sections 9,1-esting on a support of either solid metal plate or masonry and supported at the back by a metal member 19 extending transversely across and fastened to the base support of the bridge wall, as clearlyshown in Figs. 1 and 2 of the drawings, and terminating about midway of the height ofthe fire box or chamber 17 in rear of the fire box to block off and combustion chamber or space. The bridge wall 18 is backed up by the metallic angular reinforcing web or brace 19 which also kee S the wall and firebrick in place. Under or 1- nary circumstances the gases and products of combustion from the fuel on the grate 16 and in the firebox 17 pass rearwardly in the combustion chamber at and to the back of the furnace, andthen upwardly in front of the rear section wall 11. At this point the gases are dividedand pass forwardly through the outer flue openings or passes 20 to the front ofthe furnace or boiler; then the fire travel is continued from the front of the boiler rearwardly through the inner flue openings or passes 21, to the rear of the boiler and uptake to the chimney or stack. All of the seetions, aspreviously explained, are hollow for receiving the water to be heated and circulatedin a hot-water heating system or generated into steam, in a steam-heating system. The various sections are joined in airtight connection at their abutting faces 22, as indicatedat 23.

It will be noted that the intermediate sections 9 have depending hollow water legs at the sides and are provided with hollowarched ribs or drop .webs 24 below the flues 20 and 21, extending fromxnear the bottom ofthe dependingwater leg on one sideina curved form across and over the fire box or chamber, bridge wall, and combustion chamber to. near the bottom of the depen-dingleg on the opposite side so as to form a water cooled curtain in each section, but especially at the center of the firebox and combustion chamber over the firebox. The front of the fines or passes 20 and 21 are provided with cleanout doors25. The webs 24 are so positioned as to lie onopposite sides; that is, at the front and back of the bridge wall 18, so that hollow wing arches or air boxes 26 may be fitted-between pairs of webs within the opposite sides of the sections or outer portions thereof, thus causing the cooling of the hollow arches by means of contact with a pair of webs containing water. Owingto the widedifferenees in the temperatures of these parts, the sections-and webs or ribs absorb the heat of the wing arches or boxes, which istransferred to the water to give greater heating efficiency, while resting upon the bridge wall 18 and providing an inter-me diate passage or combustion space 27 therebetween forming a mixing port below the webs 24 equal to or less in cross-sectional area than either sets of fines 20 or 21, as shown, to insure proper combustion. The size and position of the hollow wing arches or air boxes 26 may be made as desired and their inward extension or adjustment regulated to give the proper size to theport or space 27. Also, the hollow wingarches or air boxes 26 may be moved in or out and any suitable means employed to fill the spaces between the outer sides of the boxes and the sides of the furnace sections within the combustion chamber in a manner very obvious to those skilled in the art. Thehollow wing arches 26 are preferably in the form of substantially rectangular boxes of metal such as cast iron of sufficient thickness to withstand the heat of the furnace without burning out, owing to the lack of presence of water therein, asisthe case with the various sections 9 composing the furnace, or may be of refractory or other tire-resisting material. Of course, the bridge wall and hollow wing arches extending inwardly from the opposite sides of the furnace into the combustion chambermay be located at any place in the boiler, according to the size of the firebox which is regulated by the capacity desired or where itis necessary to block off the reargrades to reduce the capacity inlong boilers when it is not necessary to use the full grate area. This, however, may be regulate-d according to the requirements by varying the number of sections. employed;

The hollow wing arches, as previously stated, are of hollow and substantially rectangular formation but, principally,arc constructed to conform to the interior of the sections of the furnaceso as to overlap the joint between two sections and fit snugly between then webs of said sections as is especially shown in Fig. 1 of the drawings. In the form indicated, the top ofthe box is curved as indicated at 28 to conform tothe curvature of the -furnace sections at the top, and are closed on all sides except at the outside which is left entirely open, as indicated at29, while the insides are provided with comparatively narrow vertical slots 30 centrally located and extending from top to bottom. By reason of the closed formation of the hollow wing arches and the fiat bottom walls 31 thereof,

of being facilitated. Furthermore, the outer sides are closed off from direct contact with the burnin gases and products of combustion from the firebox, but since the hollow wing arches or boxes are of heavy metal of substantial thickness up to tlu'ce-fourths of an inchor one inch or more, burning out thereof is prevented or the useful life thereof is extended for a considerable period. The cooling action caused by the contact of portions of the arches or boxes with the wate1'containing chambers of the furnace sections and especially the webs 24 thereof, also increases the useful life of the arches.

In order to supply auxiliary air, tubes or the furnace through the rear or vertical portion of the combustion chamber or flue space 34, through flues or passes 35 immediately outwardly of the webs 24 at the sides of the furnace sections through which fire travel of the gases and products of combustion is rearwa-rdly from over the firebox. The inner ends of the tubes 32 are fitted in openings 36 in the rear walls of the arches 26 so that auxiliary air will be drawn into or supplied to the interior of the latter highly pro-heated and escape in opposite directions toward each other through theslots 30. The slots 30 may be disposed to dire ct the air inwardly from the sides over the bridge wall, at'an angle of degrees or less, and the slots may be extended inwardly at right angles to the length of sides of the furnace and the combustion chamber or passage, or at an angle as shown in Figs. 3 and 5 respectively. The pipe or tube 32 may be a plain cast/metal or other pipe but is preferably fluted. or corrugated. In the form shown they are provided with spiral convexities, corrugations or convolutions 37 to cause a spiral or whirling action of the air as it passes through the same to the boxes 26 to enter into the furnace. This construction also increases the surface area of the tubes or pipes 32 with which the heated gases and products of combustion come into contact, which tubes convey the auxiliary air to the boxes 26 and are exposed to theheat of the furnace and products of combustion passing through the combustion space 34: after passing through the combustion space over the fire-box, over the bridge wall 18, between the hollow wing arches or boxes 26, and subsequently through the flues or flue openings 35, 20, and 21 before making its exit to the chimney. By having the air tubes resting 011 water backed sections at one or more points helps to keep the tubes from burning out.

The rearwardly projecting ends of the tubes 32 which may be corrugated spirally or otherwise, may be enlarged and are provided with valves or dampers 38 for regulating the supply of auxiliary air entering the furnace. In addition, damper arms 39 may be provided on the dampers and have flexible connections or chains 10 trained over pulleys 41 and connected to an automatic pressure or temperature regulator 42 provided on the boiler or furnace for controlling the action of the damper according to the steam pressure or temperature of the furnace which is set or regulated as desired. The balance beam 43 of the regulator 42, which may include a diaphragm or thermostat controlled regulator element 4:4: and has an adjustable weight 15 for regulating its action, as is well known in the art. may have connection through a chain or cord 46 with a draft door 47 whereby to open and close the latter to automatically control the draft in proportion to the fuel consumption or the amount of heat required. Obviously, the automatic control of the auxiliary air, may be associated with any automatic draft or fuel feed regulator, well known in the art, so that the auxiliary air is permitted to enter in proportion to the volume of air required for complete combustion without loss of heat and with greater efficiency owing to the complete consumption of gases and the burning of the fuel employed in the furnace. By reason of the air being discharged from the elongated slots 30 above the bridge wall or baffle 18 of firebrick or other refractory material throughout the height of the passage between the arches or boxes 26 between the bafiie and ribs or top portion of the furnace sections, the gases and products of combustion from the burning fuel on the grate 16 are thoroughly mixed with the auxiliary air to insure complete combustion and elimination of smoke passing through the flue or chimney with which the rear ends of the flues or passes 21 communicate; that is, black or carbon-containing smoke, with the escaping gases and fumes.

Thesectional base extension 7 is composed of two or more sections arranged against the damper or valve regulating the ingress of the backof the base section 7, and has top plates 7 the rear one 7' of which is inclined rearwardly to an opening in the back of the section 7'.

The rear combustion spaceis open behmd the bridge wall 18 and brace 19 to receive the deposit of ashes, soot, and other solid particles of combustion which slide down the inclined top plate 7 to the rear clean-out opening which is provided with a door 7. This provides means for efficiently and easily cleaning out the furnace, and since most of the solid particles will be deposited and removed at this point, the fines 20, 21, and 35 will require little more than dusting out. Thisstructure also permits adjustment, i. e. reduction or enlargement, of the size of the fire box and grate by using varying numbers of sections and grates 16, ordifferent sizes of base sections 7 and 7 and varying the position of the bridge wall 18 and boxes 26 thereon, the section 7 and the wall 18 serving to block off the same. This is especially desirable where the length of the boiler exceeds seventy-two inches, since restrictions are imtionfrom the burning fuel in the fire box, directly from the atmosphereand inrcar of the furnace or fire box thereof, as distinguished from in front, the same is more highly preheated and plentiful in oxygen to support combustion as compared with air drawn from the front, either above or below the fire box or ash pit where it is apt to be mixed with or contaminated by the partly burnt consumed-gases or fumes in which the propor tion of oxygen has been reduced.

IVhile I have shown and described my invention in a preferred form, I am aware that various modifications and changes may be made without departing from the spiritof the invention, the scope of which is to be determined by the appended claims.

I claim as my invention:

1. In a boiler construction of the sectional typeand each section having an inwardly projecting rib spaced from the rib of the next adjacent section, a firebox and a combustion chamber, a bridge wall bet-ween the fire box and combustion chamber and having its ends extending into the space between a pair of spaced ribs, hollow members mounted on the bridge walland extending at their outer ends into the space between said ribs, said members disposed with their inner ends approaching the center of the bridge wall to form betweensaid ends a restricted passage between the fire box and combustion chamber, and air supply means communicating with said hollow members and extending through the combustion chamber to communication with the outside atmosphereat the back of the furnace, said hollow members each provided with outlet means for air to directsaid air into the restricted passage.

2. Ina boiler construction of the sectional type, each section having an inwardly projecting rib spaced from the rib of the next adjacent section, a firebox and a combustion chamber, a bridge wall between the firebox and combustion chamber and extending into the space between a pair of ribs, members mounted on the bridge wall and interfitting members being each provided with an opening at the inside to direct said air into the restricted passage.

In a boiler of the transverse verticali sectional type, having front, back and a plurality of intermediate sections, said intermediate sectlons each having a top arch portion, depending side legjs andinwardly extending webs, the latter eing so formed that the webs of two adjacentintermediate sections are spaced; a fire wall dividing the boiler into a front fire box and rear combustion chamber and restricting the passage vertically therebetween, side members vertically alined with said wall and restricting said passage laterally, said side members being partially seated between and retained by the rality of intermediate sections, the intermediate sectionseach having a top arch portion,

depending side legs and invardlyextending webs, the webs belng so formed that a space'is left between the webs of two intermediate sections; a lower transverse fire wall dividing the boiler into a front fire box and a rear combustion chamber and restricting the passage vertically therebetween; side members vertically alined with and above said fire wall and restricting said passage laterally, said side members being partially seatedbetween and retained by the webs of two adjacent inter mediate sections, saidside membershaving air dehvery openings for dellvering air into the restricted passage; and means for supply ing auxiliary air to said side members.

5. Ina boiler of the transverse vertical sectional t pe having front, backand a plurality o intermediate'sections, the intermediate sections having a plurality of flue openings in the upper portions thereof, and provided also with transversely extending webs and within which some of said flue openings are located; a transverse lower fire wall spaced forwardly of the rear section, side members abovesaid fire wall and aimed therewith and extending partly between the webs of two adjacent intermediate sections, said sidemembers having air delivery openings adjacent the restricted passage defined by said side members and fire wall; and air conductor means to said side members, said air conductor means extending through the said flue openings in the web portions of the intermediate section rearwardly of the fire wall. I

THOMAS DAVID CASSEKLY; 

